This invention generally relates to an absorbent material, and more particularly concerns an absorbent material for use in reusable adsorbent articles for the absorption of body fluids as in medical or hygienic absorbents, for example in incontinence products, surgical dressings and sanitary products.
Absorbent materials are commonly characterized by their capacity to absorb large quantities of fluid per unit weight of material. A high degree of fluid retention is also advantageous, so that absorbed fluid is not easily released when the product is subjected to external pressure, a phenomenon known as "wetting back." Wetting back occurs when pressure is exerted onto an absorbent material wherein fluids absorbed in the material flow back to and re-wet the surface of the material. Where an absorbent material exhibits a high degree of fluid retention and no wetting back, the moisture stays trapped within the absorbent material and does not again contact the user.
Generally, absorbent materials exhibiting a high absorbent capacity are available as disposable products. Disposable products have heretofore proven capable of trapping fluids within the material and away from the user with no "wetting back." The effect is the user stays dry even after fluid is released.
Reusable absorbent materials commonly comprise textile fabrics due to the requirement that the materials must be washed and dried between uses. Reusable absorbent products have in the past been unremarkable in terms of their absorbent capacity. It is true that absorbent materials including hydrophilic fibers tend to absorb a lot of fluid. However, when fluid is absorbed by and wets fabric comprising hydrophilic fibers, there arises a tendency in hydrophilic fibers to lose strength and collapse causing the fabric to mat down. Void space in the fabric is thereby lost, reducing thickness and limiting the further amount of fluid which can be absorbed. Thus, even though the use of hydrophilic fibers enhances absorbency, absorbent materials including hydrophilic fibers tend to have less than optimum absorbency due to wet collapse.
Because of the proclivity of reusable absorbent materials to wet collapse, reusable absorbent materials tend to wet back, especially under compression. Since absorbed fluid may be forced out of reusable absorbent material by pressure, reusable absorbent products have been unable to produce a stay-dry effect with no wetting back.
Further, reusable absorbent products have proven to be uncomfortable. When a material comprising textile fabrics gets wet it stays wet throughout its entire thickness so that if a user wearing an incontinence garment releases fluid, the wet fabric stays against the user's skin.
Hence reusable absorbent products have heretofore not been accepted as a satisfactory replacement for disposable absorbent products.
For the foregoing reasons, there is a need for a reusable absorbent material exhibiting a high degree of absorbency for removing fluid from the surface of the absorbent material and away from the user's skin. The material must move the liquid rapidly and permanently away from the surface with no wetting back thereby providing a dry surface against the user. The reusable absorbent material having this stay-dry effect must also be easy to manufacture.